This invention concerns an engine compartment casing element, in particular for sound absorption, with a foamed material element attached to a wall element which preferably reflects sound, the foamed material element having a skin-like covering on the side facing away from the wall element, the side exposed to the sound waves.
Such an engine compartment casing element is known from European patent 131 616 for example. In that patent the foamed material element consists of foamed material throughout. The foamed material has the same thickness and is free of perforations throughout. A sealed-in grid layer is provided to stabilize the foamed material. It is also known that elements absorb airborne noise by placing sheeting on a hump-like design of an insulating material, for example a foamed material, so the sheeting can basically vibrate freely. In this regard, reference is made to French patent 77 30 604 and German patent 32 19 339 as examples. Furthermore, it is also known from Kurtze, Physik und Technik der L armbek ampfung (Physics and Technology of Noise Control), published by G. Braun, Karlsruhe, 1964, page 159, that sheeting which is supported on the edges by porous soundproofing material is to be provided in the case of sheet resonators attached directly to a wall surface.